Transportable and assemblable bridges are known which can provide a path for pedestrian, bicycles, light or heavy vehicles, across and over obstacles such as rivers and ravines. Some example of previous invention of prefabricated unit construction modular bridging systems may be found in U.S. Pat. Nos. 4,912,795/5,414,885/6,009,586/4,965,903/6,308,357/6,631,530 and 5,924,152.
Most of the time, fusion welding is employed to assemble such structures. However, it is well known in literature that aluminum fusion welding partially anneals the weld zone by creating a heat-affected-zone on the base metal which decreases its ultimate and yield strengths (example can be read in Dispersoid-Free Zones in the Heat-Affected Zone of Aluminum Alloy Welds—B. C. MEYER, H. DOYEN, D. EMANOWSKI, G. TEMPUS, T. HIRSCH, and P. MAYR). The present invention allows the fabrication of such structure using the full strength of aluminum because no welding for the main bearing structure would be required anymore. As an additional feature, the invention could allow anodizing, bake paint finished and easy transportation of all components to the erection site. The fabrication of all components could also be made by numerically controlled technologies that could increase accuracy as well as minimizing the fabrication time. Most of these additional features are not always possible for conventional aluminum welded structures since large structures request special transportation or would not fit into anodizing baths or on automated bake paint lines.
Another important advantage is that the invention allows all elements to be joined quickly together on site with a minimum of fasteners to form a bridge of the required length and strength within the overall limitations of the system whether it is made of aluminum, steel or other suitable material.